Internal combustion engine



Aug. 9, 1938. P. LORANGE I ,1 3

INTERNAL COMBUSTION ENGINE Filed Dec'. 4, 1935 2 Sheets-Sheet 1 Au9,1938. P. LORANGE 2,126,483

INTERNAL COMBUSTION ENGINE Filed Dec. 4, 1935 2 Sheets-Sheet 2 providedwith a precombustion chamber.

Patented Aug. 9, 1938 INTERNAL COMBUSTION ENGINE Prosper LOrange,Stuttgart-Feuerbach, Germany Application December 4, 1935, Serial No.52,839.

' In Germany August 12,1935

Claims.

Attempts to reduce the weight of Diesel engines are met withdifllcultles mainly on account of the high pressure produced in thestarting of the engine. This pressure is due to the high temperaturerequired for starting and further to the retardation of the ignitionwhich occurs with cold engine and which then brings about a rapidcombustion and a consequent rapid rise in the pressure; When the machineis warm the pres:- sure is automatically reduced; and it is alsopossible to reduce the pressure by throwing a cylinder intocommunication with an additional clearance space.

In order to allow starting with warm engine it is possible, either towarm the machine itself or to warm the charging air, but this requiresheavy electric batteries or other additional, complicated and expensiveapparatus.

The problem of weight reduction occurs mostly in connection withmulti-cylinder engines for aircraft and the like, and the object of theinvention is to achieve such reduction in connection with engines ofthis type.

For this purpose only one, forinstance, of the cylinders is accordingtothe invention designed,

as a normal, high-compression cylinder, and means are provided forwarming, and if need be diluting, the charging air for the othercylinders, during the starting of the engine, by means of the exhaustgases from the high-compression cylinder. Q

By mixing the charging air of the low-compression cylinders with exhaustgases from the high compression cylinder, the air will not only be warmbut the oxygen content thereof will be diluted. Both actions tend toreduce the maximum pressure in the cylinders atstarting, partly becauseof the dilutionof the oxygen content and partly because the warming ofthe air leads to less retardation of the ignition.

A six cylinder engine, without OOlIlDl'GSSOIyES used in aircraft, may betaken as an example. One of the cylinders is adapted for normalhighcompression with a ratio of 1:18 and may be The other cylinders havea compressionratio of 1:12 and a volume 30% larger than the firstmentioned cylinder. Thus, if the first cylinder has a volume V, thevolume of the six cylinders together will be V+(5 1.3xV)=7.5 V, i. e.,25% more than the volume. of six high-compression cylinders. Theoperation is then asfollows:

1. In starting the engine by hand or electrically, fuel is first fedonly to the high compression cylinder. 7

2. When the engine has started and as soon as the exhaust gases from thehigh-compression cylinder appear clean, the gases are led by means ofthe controlling device to a mixing chamber from which the remainingcylinders receive their supply of air, the air being thus mixed with theexhaustgases.

3. After a few strokes of the engine, the lowcompression cylinders arefed with fuel, abouthalf the full amount. 10

4. When the engine has been heated up suiiiciently, the exhaust of thehigh-compression cylinder is diverted, either by hand or by thermallyoperated means, to the atmosphere, so that the other cylinders will befed with pure air. At the same time the low-compression cylindersare'given their full supply of fuel. The change over may be gradual ifdesired.

The engine will now work normally with one high-compression and fivelow-compression cylfor restarting with low-compression. This is eifectedautomatically.

Numerically the procedure is as follows:

The exhaust gas from the fully loaded highcompression cylinder has atemperature which is sufllcient to raise the temperature of the air andgas mixture received by the other cylinders to about 150 C. This mixturehas the volume V of the first cylinder plus the increase obtained by theheating and plus 5X 1.3 V of the fresh air raised to the sametemperature. Thus the mixture is attenuated by the heating by about andby the admixture of more than 25% exhaust gas by another 25%, l. e., theoxygen content of the heated mixture is about %X /4= /z of that 40 ofthe same volume of a cold air charge.

The compression brings about a' further increase in the temperature, sothat the mixture will finally have a temperature which is higher thanthat in the high compression cylinder. Thus the ignition will take placewith less retardation, and the maximum pressure will therefore,particularly in view of the low oxygen content, be very low.

The above described engine will be lighter than a normal engine, and itcan be started with equal facility. The chamber in which the air ismixed with the exhaust gas adds but little to the weight. Instead ofthis chamber a heat exchanger may be used for warming the air adiagrammatic view of an engine constructed according to the invention.

Fig. 2 is a diagram of the fuel pump and the controlling device.

Fig. 3 illustrates a form of heat exchanger, and

Fig. 4 is a detail sketch of a portion of Fig. 1.

The illustrated engine is provided with a cylinder A, working withhigh-compression, and with five cylinders B, working withlow-compression. For this purpose the clearance space of the cylinder Ais restricted as compared with that of the cylinders B. The cylinder Areceives atmospheric air at C either direct or from a pre-compressor.The cylinders B receive air at D from a mixing chamber E whichcommunicates at R either with the atmosphere or with a pre-compressor.Into this chamber opens aconduit F which is branched of! at G forconnection to the exhaust pipe H of the cylinder A as well as to theatmosphere. Throttle valves J and K are provided for leading the exhaustgas either through the conduit F into the chamber E or past the valve Kinto the atmosphere or into a discharging fan. The fuel pump P (Fig. 2)has a pump element Q which supplies fuel to the cylinder A, and pumpelements which supply fuel to the cylinders B. The pump elements 0 arecontrolled by a slidable rod N which is operated by a bell crank U.Another rod M, operated by a bell crank T, controls the pump element Q.The bell cranks, as well as operating members for the throttle valves Jand K. bear by spring pressure against a cam rail V which is slidablyoperated for controlling the engine.

One neutral and four operative positions of the cam rail are indicatedin the drawings, and the conditions prevailing in the differentpositions are as follows:

Position 0: The fuel pump is inoperative; and

the valve K is open; and the valve J is closed.

Position l The bell crank T gives the pump element Q full feed; thevalve K is open; and the valve J is closed; the engine starts.

Position 2: (Illustrated position). The bell crank T gives the pumpelement Q full feed; the valve K is closed; the valve J is open; and theengine gathers up speed and heat.

Position 3: The bell crank T remains as before; the bell crank U giveshalf feed to the pump elements 0; the valve K'is closed; and the valve Jis open.

Position 4: The bell crank '1 remains as before; the bell crank U givesfull feed to the pump elements 0; the valve K is open; and the valve Jis closed. v

For idle running, the cam rail is moved to the position 2. For stopping,the rail is moved to the position 0.

Instead of the illustrated six cylinder engine, a five or sevencylinder, radial engine may be employed and so the invention applies toengines having radially arranged as well as juxtaposed cylinders.

When the engine works with small load, the valves K and J may bemaintained in intermediate positions, so that some amount of exhaust gaswill be fed to the low-compression cylinder.

I claim:

1. An internal-combustion engine of the compression-ignition andconstant pressure cycle type having a plurality of working cylindersarranged in two sections working with different compression, means forfeeding fuel separately to the two sections, an air chambercommunicating with the atmosphere and with the low compression sectionfor supplying charging air to the cylinders of said section, and meansfor heating the air in said chamber by the exhaust gases from the highcompression section.

2. A structure as claimed in claim 1 wherein the means for heating theair comprises an exhaust pipe arranged to discharge the gases into theair chamber.

3. A structure as claimed in claim 1 wherein the means for heating theair comprises a heat exchanger located within the air chamber.

4. A structure as claimed in claim 1 wherein the high compressionsection comprises a single cylinder and the low compression section, aplurality of cylinders.

5. An internal-combustion engine of the compression-ignition andconstant pressure cycle type having a plurality of working cylindersarranged in two sections adapted to work with different compression, anair chamber supplying charging air to the cylinders of the lowcompression section, means for heating the air in said chamber by heattransmission from the exhaust gases coming from the high compressionsection and adapted to lead the air in counter-current to the heatinggases, means for supplying fuel to the cylinders, means for regulatingthe fuel supply separately to each section of the cylinders, valves .forcontrolling the exhaust from the high compression section, and acontrolling member for said valve and.fuel regulating means operative,on starting the engine, first to connect the high compression sectionwith the fuel supply, then to set the valves for leading exhaust gasesfrom the high compression section to said air chamber, then to connectthe low compression section with the fuel supply, and finally todisconnect the air chamber from the exhaust.

I PROSPER L'ORANGE.

